Free-standing tub



FIG. 1 is a top, rear, and partial side perspective view of a free-standing tub showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side view, the opposite side being a mirror image thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a rear elevational view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken line showing is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a free-standing tub, as shown and described. 